Excello Mill vari speed repair questions

Rangerjoe2

Rangerjoe2

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Finally bit the bullet and tore into the vari speed drive on the top of my mill. I just couldn't take the noise coming from it. I bought a lazer rpm meter so I could verify the spindle speeds on my lathe and mill especially the impact that changing the hrtz has on the speed. Pretty happy with the information I gleaned from the lathe and will be making myself a speed chart to utilize but got some puzzling results out of the mill. I found that the spindle speed vs. The spindle speed reading on the drive is way off. I'm talking double the actual speed the mill says it should be.

Puzzled by this I decided to try and get the upper portion apart which was actually pretty easy. I'll post some pics when I get home but the upper puleyl that moves up and down had a lot of play and thus noise at high speed. I found the two plastic bushings, one on the top and the other on the bottom end of the pulley housing, that I assume are to prevent excess movement or wobble yet allow the pulley to slide up and down on the spindle shaft. I also wondered if the belt was the correct belt for the machine since the speeds were off so far. I found a post that gave a different belt number and size than the one on my machine. The belt I found was listed for the 2hp motor on my mill. Needless to say it has been ordered.

So here's my question...how much play do I want between the shaft and the pulley to allow it to slide but not wobble?

Also, I may just continue on with disassembly of the entire head to allow me to replace any seals etc. Also the down feed is kinda finicky so I may crack into that as well. Really didn't want to tear into this thing but that's life.

Joe
 
20141022_140920.jpg20141022_140904.jpg20141022_140920.jpg20141022_140904.jpgHere are some photos of the upper pulley and the p lactic shims i need to replace. My plan was to measure the shaft then measure the inside of the pulley with the shims installed to see how much play there is. I'm thinking of making some brass shims that will give me .001 or .0005 clearance. Any thoughts?

20141022_140920.jpg 20141022_140904.jpg
 
I have a 602 also. I rebuilt mine two years ago. My bushings wore out too. Guess we have a lot in common :)

Being a cheap bastid, I made new bushings myself. Don't have a spec for you, I just made them so they slid nicely. probably 3 thou clearance???

i have an entire machine that's just a boneyard donor if you need to buy something unusual.

My spindle bearings were shot. Bet i searched eBay for a month getting all four.

The power drawbar extension part on the spindle is a LEFT hand thread. I learnt the hard way what happens when you apply too much torque CW to a left hand thread. that little part was a stone ***** to fabricate.

Karl

PS I added a spindle readout to mine, the dial isn't even close - way low

excello.jpg
 
Karl

what did you make the bushings out of? Shim stock? Also, where did you find the seals etc? I have the part numbers I'm hoping I can find a comparable parts by searching those numbers.
 
Your pulley looks slightly different. Now i wonder if I was the second guy there. Mine was turned a bit larger where you have the shim. Anyway, I just made it out of mystery metal (grab something out of the stock bin). It was maybe 0.050" thick with a 0.250" where it was 0.125 thick on one end. Kind of "L" shape cross section. These numbers are pure guesses from something I did two winters ago.

I'll double check in the morning if the other head has this laying separate and look at it.

I have the manual but its too big to attach on this forum. Excello still stocks parts. Maybe you want to just buy this part. PM me your email address and you can have it.


The bottom seal on the head leaked like a sieve. The one from McMaster wasn't an exact match so I went to a bearing supply place and did show and tell. They found it.

BTW, there's a trick to putting this back together. You need to block the vari speed pulleys wide open in such a way so you can pull the spacer out when its laying almost together. Took me a couple trials.
 
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Gonna order a chunk of brass and make some shims. I was hoping I could find some and just cut to size, but no good. The thickest I can find is .031 and I need .0535. Also, I was looking to replace the bearing that supports the top pulley from the vari speed fork. The number listed on the bearing is MRC C011KS but I can't source that either. I'm also considering just converting the entire vari speed over to a 1:1 pulley system and using the vfd to control the speeds.
 
Losing the varispeed and using only the VFD will work but you'll loose some spindle torque. May not be an issue for you.

I like to ruff parts with Sandvick R390 inserts on a one inch or one and half inch endmills. The Excello is only a four horse machine, its pretty easy to push this cutter till you loose 10% of your spindle speed and have full amps. I never get tired of seeing how fast metal can be removed.

BTW, you're smarter than me, brass is the right choice for this part.

Karl
 
I made some bushing today for the varispeed pulley. Man what a huge improvement. I made them out of 6061 aluminum. I still need to replace the bearing on top of the drive but I can't find one anywhere. Anyone have any suggestions?
 
Mike ID, OD, width, and post a pic here. I have a bearing book, I'll look it up.

I can't remember did you already post what numbers are on this bearing? That info will help too.

If i can't find it, I'll give you the one from my parts donor head.

Karl
 
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